package com.example.yiparkapplication.tool;

import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;

import java.util.Random;

public class IdentifyingCode {

    private static final char[] CHARS = {
            '0','1','2', '3', '4', '5', '6', '7', '8', '9',
            'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'j', 'k', 'm',
            'n', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
            'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M',
            'N', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z'
    };

    //这就是个单例模式
    private static IdentifyingCode Identifyingcode;

    public static IdentifyingCode getInstance(){
        if (Identifyingcode==null){
            Identifyingcode = new IdentifyingCode();
        }
        return Identifyingcode;
    }

    private static final int CODE_LENGTH = 4;
    private static final int FONT_SIZE = 50;
    private static final int LINE_NUMBER = 5;
    private static final int BASE_PADDING_LEFT = 10, RANG_PADDING_LEFT = 100, BASE_PADDING_TOP = 75, RANGE_PADDING_TOP = 50;
    private static final int DEFAULT_WIDTH = 400, DEFAULT_HEIGHT = 150;
    private int width = DEFAULT_WIDTH, height = DEFAULT_HEIGHT;
    private int base_padding_left = BASE_PADDING_LEFT, rang_padding_left = RANG_PADDING_LEFT,
            base_padding_top = BASE_PADDING_TOP, range_padding_top = RANGE_PADDING_TOP;
    private int codeLength = CODE_LENGTH, line_number = LINE_NUMBER, font_size = FONT_SIZE;

    private String code;
    private int padding_left, padding_top;
    private Random random = new Random();

    public Bitmap createBitmap(){
        padding_left = 0;
        padding_top = 0;
        Bitmap bp = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
        Canvas c = new Canvas(bp);

        code = createCode();

        c.drawColor(Color.WHITE);
        Paint paint = new Paint();
        paint.setAntiAlias(true);
        paint.setTextSize(font_size);

        for (int i=0;i<code.length();i++){
            randomTextStyle(paint);
            randomPadding();
            c.drawText(code.charAt(i) + "", padding_left, padding_top, paint);
        }

        for (int i=0;i<line_number;i++){
            drawLine(c, paint);
        }
        c.save();
        c.restore();
        return bp;
    }

    private String createCode(){
        StringBuilder sb = new StringBuilder();
        for (int i=0;i<codeLength;i++){
            sb.append(CHARS[random.nextInt(CHARS.length)]);
        }
        return sb.toString();
    }

    private void randomTextStyle(Paint paint){
        int color = randomColor();
        paint.setColor(color);
        //随机字体粗细
        paint.setFakeBoldText(random.nextBoolean());
        double skew = random.nextInt(11)/10;
        //正数表示左倾斜角，负数为右倾斜角
        skew = random.nextBoolean()?skew:-skew;
    }

    private int randomColor(){
        return randomColor(1);
    }

    private int randomColor(int rate){
        int red = random.nextInt(256) / rate;
        int green = random.nextInt(256) / rate;
        int blue = random.nextInt(256) / rate;
        return Color.rgb(red, green, blue);
    }

    private void randomPadding(){
        padding_left += base_padding_left + random.nextInt(rang_padding_left);
        padding_top += base_padding_top + random.nextInt(range_padding_top);
    }

    private void drawLine(Canvas canvas, Paint paint){
        int color = randomColor();
        int startX = random.nextInt(width);
        int startY = random.nextInt(height);
        int stopX = random.nextInt(width);
        int stopY = random.nextInt(height);
        paint.setStrokeWidth(1);
        paint.setColor(color);
        canvas.drawLine(startX, startY, stopX, stopY, paint);
    }

    public String getCode(){
        return code;
    }

}
